لخّصلي

Semantic Analysis The Semantic analysis phase of compiler connects variable definition to their uses, and checks that each expression has a correct type.If both operands of the arithmetic operators "addition" , "subtraction", and "multiplication" are of type integer then the result is of type integer.This checking called "static type checking" to distinguish it from "dynamic type checking" during execution of target program. This phase is characterized be the maintenance of symbol tables mapping identifiers to their types and locations. Semantic Analysis Example of static type checking: 1- Type checks:- A compiler should report an error if an operator is applied to an incompatible operand. 2- Flow of control checks:- Statements that cause flow of control leave construct must have some place to which to transfer the flow of control . For example, a "break" statement in 'C' Language causes control to leave the smallest enclosing while ,for ,or switch statement.Semantic Analysis Example of static type checking: 3- Uniqueness checks:- There situations in which an object must be defined exactly once.Semantic Analysis ?

Semantic Analysis
The Semantic analysis phase of compiler connects variable
definition to their uses, and checks that each expression has
a correct type.
This checking called "static type checking” to distinguish it
from “dynamic type checking” during execution of target
program. This phase is characterized be the maintenance of
symbol tables mapping identifiers to their types and locations.
Semantic Analysis
Example of static type checking:
1- Type checks:- A compiler should report an error if an operator is
applied to an incompatible operand.
2- Flow of control checks:- Statements that cause flow of control
leave construct must have some place to which to transfer the
flow of control .
For example, a “break” statement in ‘C’ Language causes control
to leave the smallest enclosing while ,for ,or switch statement.
Semantic Analysis
Example of static type checking:
3- Uniqueness checks:- There situations in which an object must be
defined exactly once. For example in ‘Pascal’ Language an
identifier must be declared uniquely.
4- Name related checks:- Sometimes, the same name must appear
two or more times. The compiler must check that the same name
Is used at both places.
Semantic Analysis
Type system:-
The design of type checker for a language is based on
information about the syntactic construct in the language, the
notation of types, and the rules for assigning types to language
constructs.
The following excerpts are example of information that a
compiler writer might have to start with
 If both operands of the arithmetic operators “addition” ,
“subtraction”, and “multiplication” are of type integer then the
result is of type integer.
Semantic Analysis
 The result of Unary & operator is a pointer to the object
referred to by the operand. If the type of operand is T, the
type of result is pointer to T.
We can classify type into:
1- Basic type: this type are the atomic types with no internal
structure , such as Boolean, Integer, Real, Char, and a special
basic types ”type-error, void”.
2-Construct types: Many programming Languages allows a
programmer to construct types from basic types and other
constructed types. For example array, struct.
Semantic Analysis
3- complex type: Such as link list, tree, pointer.
Type system:- is a collection of rules for assigning type
expressions to the various parts of a program. A type checker
implements a type system.